The Impact of Injuries on Betting

On Sunday, May 3, Golden State beat Memphis 101-86 in Game 1 of their Western Conference semi-final series. When news that Grizzlies guard Mike Conley would miss the game because of a left eye problem became public, the spread moved a point or two.

It didn’t matter in the end. The Warriors covered both the initial and the revised line. However, there are certainly times when injury news should effect your wagers.

Marquee Players Tend to Be Overvalued:

In all sports, the public overreacts to injuries when they impact marquee players. Because we are a fantasy sports culture, fans perceive the absence of, say, Cam Newton or Yasiel Puig as a lot more important than it actually is. While they are both excellent players, perhaps the most important guys on their team, it doesn’t mean their clubs are vastly different without them. Case in point: Derek Anderson was 2-0 as the Carolina starter last year and the Dodgers record without Puig is plenty good enough to lead the NL West this season.

Role Players Tend to Be Overlooked:

Conversely, an injury to a key lineman, or a catcher who pitchers feel comfortable with but doesn’t produce huge offensive numbers will be under appreciated by general bettors. Any prolonged absence of Steph Curry or Klay Thompson would hurt the Warriors, and everyone would recognize the impact of missing those sharpshooters. Far fewer people would understand how Golden State would be impacted if Draymond Green’s tight man-to-man defense, or Andrew Bogut’s rim defending disappeared.

Sportsbooks and the Public Tend to Have the Same Intel around the Same Time:

It is also vital to remember that injuries are factored into betting lines, usually quite quickly, though not immediately. If something surprising happens – say a player that was injured is suddenly ok to play, or someone thought to be healthy is scratched – then there can be value in betting before the line gets adjusted. However, most everyone knew that Drew Stanton wasn’t playing in last year’s Arizona Cardinals playoff game and sportsbooks posted a line that indicated Ryan Lindley would start. Carolina still covered, and Lindley was historically bad, but it wasn’t as if bettors “got away” with wagering on a faulty line.

The Moral of the Story:

Like most bets, when you recognize a player either won’t be on the field, or may not be fully healthy, it is important to take a broad look at the game, using the injury as a small piece to a large puzzle. It is import to assess what role the sidelined player performs, how good the replacement player is, what the match-up with the team’s opponent now looks like, and use that analysis as a guide to your bets.

Recognizing that injured stars are over-emphasized by the public and media, and that less noteworthy players are apt to be undervalued, can give you a small edge when betting. In a game of margins, a small edge can make a big difference.